json field in DAL, thanks Alan

VERSION

@@ -1 +1 @@
-Version 2.4.1-alpha.2+timestamp.2013.01.08.09.16.57
+Version 2.4.1-alpha.2+timestamp.2013.01.08.09.22.34

gluon/serializers.py

@@ -20,6 +20,10 @@ except ImportError:
         import contrib.simplejson as json_parser    # fallback to pure-Python module
 
 
+def loads_json(o):
+    # deserialize a json string
+    return json_parser.loads(o)
+
 def custom_json(o):
     if hasattr(o, 'custom_json') and callable(o.custom_json):
         return o.custom_json()

gluon/sqlhtml.py

@@ -30,6 +30,7 @@ from utils import md5_hash
 from validators import IS_EMPTY_OR, IS_NOT_EMPTY, IS_LIST_OF, IS_DATE, \
     IS_DATETIME, IS_INT_IN_RANGE, IS_FLOAT_IN_RANGE, IS_STRONG
 
+import serializers
 import datetime
 import urllib
 import re
@@ -39,6 +40,9 @@ import inspect
 import settings
 is_gae = settings.global_settings.web2py_runtime_gae
 
+
+
+
 table_field = re.compile('[\w_]+\.[\w_]+')
 widget_class = re.compile('^\w*')
 
@@ -164,11 +168,9 @@ class TimeWidget(StringWidget):
 class DateWidget(StringWidget):
     _class = 'date'
 
-
 class DatetimeWidget(StringWidget):
     _class = 'datetime'
 
-
 class TextWidget(FormWidget):
     _class = 'text'
 
@@ -184,6 +186,22 @@ class TextWidget(FormWidget):
         attr = cls._attributes(field, default, **attributes)
         return TEXTAREA(**attr)
 
+class JSONWidget(FormWidget):
+    _class = 'json'
+
+    @classmethod
+    def widget(cls, field, value, **attributes):
+        """
+        generates a TEXTAREA for JSON notation.
+
+        see also: :meth:`FormWidget.widget`
+        """
+        if not isinstance(value, basestring):
+            if value is not None:
+                value = serializers.json(value)
+        default = dict(value=value)
+        attr = cls._attributes(field, default, **attributes)
+        return TEXTAREA(**attr)
 
 class BooleanWidget(FormWidget):
     _class = 'boolean'
@@ -235,7 +253,6 @@ class OptionsWidget(FormWidget):
                 raise SyntaxError(
                     'widget cannot determine options of %s' % field)
         opts = [OPTION(v, _value=k) for (k, v) in options]
-
         return SELECT(*opts, **attr)
 
 
@@ -843,6 +860,7 @@ class SQLFORM(FORM):
     widgets = Storage(dict(
         string=StringWidget,
         text=TextWidget,
+        json=JSONWidget,
         password=PasswordWidget,
         integer=IntegerWidget,
         double=DoubleWidget,

gluon/validators.py

@@ -21,6 +21,16 @@ import unicodedata
 from cStringIO import StringIO
 from utils import simple_hash, web2py_uuid, DIGEST_ALG_BY_SIZE
 
+JSONErrors = (NameError, TypeError, ValueError, AttributeError,
+              KeyError)
+try:
+    import json as simplejson
+except ImportError:
+    from gluon.contrib import simplejson
+    from gluon.contrib.simplejson.decoder import JSONDecodeError
+    JSONErrors += (JSONDecodeError,)
+
+
 __all__ = [
     'CLEANUP',
     'CRYPT',
@@ -53,6 +63,7 @@ __all__ = [
     'IS_UPLOAD_FILENAME',
     'IS_UPPER',
     'IS_URL',
+    'IS_JSON',
 ]
 
 try:
@@ -300,6 +311,30 @@ class IS_LENGTH(Validator):
         return (value, translate(self.error_message)
                 % dict(min=self.minsize, max=self.maxsize))
 
+class IS_JSON(Validator):
+    """
+    example::
+        INPUT(_type='text', _name='name',
+            requires=IS_JSON(error_message="This is not a valid json input")
+
+        >>> IS_JSON()('{"a": 100}')
+        ('{"a": 100}', None)
+
+        >>> IS_JSON()('spam1234')
+        ('spam1234', 'invalid json')
+    """
+
+    def __init__(self, error_message='invalid json'):
+        self.error_message = error_message
+
+    def __call__(self, value):
+        try:
+            simplejson.loads(value)
+            return (value, None)
+        except JSONErrors:
+            pass
+        return (value, translate(self.error_message))
+    
 
 class IS_IN_SET(Validator):
     """